FR 2933539 and FR 2936363 describe a magneto-caloric effect type heat pump apparatus applied to a vehicle as a thermo-magnetic cycle apparatus that uses temperature characteristics of a magnetic element. FR 2933539 has the corresponding publications WO 2010/004131 and US 2011/0104530. FR 2936363 has the corresponding publications WO 2010/061064 and US 2011/0215088.
FR 2936364 describes a structure of a magneto-caloric element, and has the corresponding publications WO 2010/034907 and US 2011/0173993. The magneto-caloric element has plural element units respectively have Curie temperatures different from each other, and the plural element units are arranged in order of the Curie temperature.
JP-B2-4234235 and JP-A-2002-281774 describe a thermo-magnetic engine as a thermo-magnetic cycle apparatus that uses temperature characteristics of a magnetic element.
The magneto-caloric element of FR 2936364 has the distribution in the Curie temperature, and the distribution corresponds to a temperature distribution generated between a high temperature end and a low temperature end of the element. In this case, high magneto-caloric effect can be achieved by the magneto-caloric element.
However, if the temperature of the high temperature end or the low temperature end is varied, the magneto-caloric effect is lowered. For example, in the magneto-caloric effect type heat pump apparatus, a temperature of a heat source and a temperature of a thermal load easily vary. More specifically, in a case where the magneto-caloric effect type heat pump apparatus is used in an air-conditioner, outside air temperature and inside air temperature vary. If the temperature of the high temperature end or the low temperature end is varied, the magneto-caloric element cannot work in an optimal temperature range, so that performance of the magneto-caloric effect type heat pump apparatus including the magneto-caloric element may be lowered.